I found the solution (I already had this problem but I couldn't remember the right code)

mat [c4d.MATERIAL_TRANSPARENCY_COLOR] = c4d.Vector (1.0, 1.0, 1.0) #color white
mat.Update (True, True)

I found the solution to my problem, on the internet, with code samples:
https://www.c4dcafe.com/ipb/forums/topic/101805-materials-and-shaders-with-python/

I am going to write a new script, using c4d.CallCommand and c4d.utils.SendModelingCommand which can do the same thing much faster.
The Script log window presents the code very well, in real time, for many operations.

@cairyn said in Polygon corresponding to a selection:

SendModelingCommand

Indeed, with SendModelingCommand it would be faster.
I don't remember how we visualize with C4D the python code corresponding to the actions of the keyboard and the mouse.

Hi,

I would like to know if we can quickly obtain a polygon corresponding to a selection.

I manage to do it in python, but for the large meshes it's much too slow, because I do treatments on the indices of points and faces.

Below, with python, I create two polygons with the corresponding material, for the two selections (selection_1 and selection_2)
For a large mesh (greater than 100 Mo), the use of indices for points and faces considerably slows down the program.

We see that the initial polygon has been divided correctly, according to the two selections

Thank you.
I had forgotten about this excellent feature of C4D.
It must be said that I rarely do plugins, because now C4D can do a lot of things.

Hi,

I have another problem that looks a bit like my previous post.
Now for each tag (type 5616), I want to know the name of the associated selection, if it exists.
Could you put the correct code in place of the dotted lines

	tag = obj.GetFirstTag()
	while tag:
		if tag.GetType() == 5616: #texture tag
			
			#name of tag
			print tag.GetMaterial().GetName()
		
			#name of the associated selection, if it exists 
			...
			...
			...			

		tag = tag.GetNext()

Thanks for your quick replies

I used GetBaseSelect() which allowed me to have the selected faces for each selection

		list_polygon = obj.GetAllPolygons() 
		dim = len(list_polygon)

		L = []
		tag = obj.GetFirstTag()
		while tag:
			if tag.GetType() == c4d.Tpolygonselection:
				sel = tag.GetBaseSelect()
				L2 = []
				for i in range(0,dim):
					if sel.IsSelected(i):
						L2.append(i)
						
				L.append([tag.GetName(),L2])
			tag = tag.GetNext()	
			
		for item in L:
			print item[0]
			print item[1]

Hi,

I have a polygon with multiple selections.
For each selection, I want to know the list of faces (presented as a list of indices)

For a polygon I know how to access each selection:

tag = polygone.GetFirstTag()
while tag:
	if tag.GetType() == c4d.Tpolygonselection:
	print tag.GetName()
	..
	...
	...
	tag = tag.GetNext()

If you can replace the dotted lines with the correct code, thanks

I found the solution to my problem, on the internet, with code samples:
https://www.c4dcafe.com/ipb/forums/topic/101805-materials-and-shaders-with-python/

Hi

I created a material.
I inserted a texture into the COLOR channel.
Then, I inserted another texture into the BUMP channel.

Now, I want to insert a texture for the specularity, but I don't know how to create a Layer Reflection (Legacy)
I only activated the REFLECTANCE channel with the following code:

mat [c4d.MATERIAL_USE_REFLECTION] = True

Then I want to apply the following values for this layer:

0.5 for REFLECTION_LAYER_MAIN_VALUE_ROUGHNESS
1.0 for REFLECTION_LAYER_MAIN_VALUE_REFLECTION
0.2 for REFLECTION_LAYER_MAIN_VALUE_SPECULAR
1.0 for REFLECTION_LAYER_MAIN_VALUE_BUMP

I suppose that these values must be prefixed by the variable 'mat' which represents the material and also by the id of the layer.

I found the solution (I already had this problem but I couldn't remember the right code)

mat [c4d.MATERIAL_TRANSPARENCY_COLOR] = c4d.Vector (1.0, 1.0, 1.0) #color white
mat.Update (True, True)